Tttnnel kiln



W. L. HANLEY. JR

March 19, 1929.

TUNNEL KILN Original'Filed Aug. 30

3 Sheets-Sheet @awww UHIIUUWIIIIUIIHH nu March 19, 1929. w, L HANLEY, AJR 1,705,475

TUNNEL KILN Original Filed Aug. 50, 1926 5 Sheets-Sheet 2 TOR ATTORNEY W. L. HANLEY, JR

`March 19, 1.929.

TUNNEL KILN 1 Filed Aug. 50, 1926 3 Sheets-Sheet :.gina.

ENTOR XSQWWRNEY Patented Mien 19, i929,

TVQS

.Maar eri-Ti,

TUNNEL KILN.

Application led AugustO, 1926, Serial No. 132,392. Renewed August 8, 1928.

My invention consists in the novel features hereinafter described, reference being had to the accompanying drawings which illustrate several embodiments ofthe invention selected by me for purposes of illustration, and the said invention is fully disclosed in the followingdescription and claims.

The object of my invention is to produce a tunnel kiln especially adapted for the firing of bricks and other coarse clay and ceramic products. ln the construction of such kilns, a simple and economie structure is particularly'desirahle in order to minimize the initial Vcost of the kiln, and the expenses of upkeep and repair, and it is alsoof great importance Y to. obtain the highest ei'licicncy of the heating means employed for firing the kiln, and to utilize the heat thereof to the greatest pos- Y sible advantage, in order to keep down the expenses of operation. One of the important features of my presentinvention is, that l heat the tiring zoneV or zones yof the kiln by furnaces which discharge their products of combustion directly into the goods space thereof, and the hot products of combustion, after imparting their greatest heat to the ware within the iiring zone or zones, are withdrawn therefrom and conducted to and discharged into a preheating zone or zones, so that the heat of such products of combustion remaining therein, may be utilized in preheating the unred ware on its way to the firing zone, and gradually effect the preheating, oxidation, and Water-smokof the unfired Ware and bring it up to a temperature approximately that of the entering end of the contiguous firing zone, the fresh air to provide the vnecessary oxygen to elect the` oxidation ofthe Yware and prevent scumniingor staining it, being introduced into lthe preheating zone or zones With the iet products of combustion, or separately therefrom, or both.v i

My invention also'contemplates the emw ployment in conjunction with the means for conveying the hot products of combustion to a preheating zone of air injecting means, for supplying oxygen'to the prelieating zone and simultaneously creating the necessary suction in the eduction passages for Withdrawing the het jn fliicts ofxcoinbustion from the firing` zone, to eiieet such withdrawal.

My invention also contemplates the employment of,v a single air forcing apparatus Y for supplying air to said injecting nozzles,

ployed in heating the firing zone, and for any auxiliary an* inlet passages connected with the preheating zone, thus avoiding the vduplication of air forcing devices which is customary in connection with tunnel kilns.

My invention is applicable to twin tunnel kilns provided with parallel goeds conveying means movable in opposite directions there* through, in which case the hotfired Ware after passing from one of the firing zones, Will in cooling giveI up heat for preheating, water-smoking, and oxidizing the incoming unfired ware in each of the end portions of the kiln, in addition to the means previously referred to.

My inven 'on also applicable to single tunnel kilns, in which the preheating, oXidation, and watcrfsinoking of the unlired f'are may be acconilplished entirely by means of the' hot products of combustion, Withdrawn from the iii-ing zonein the manner previously described, and admitted with air into the preheating zone., or in addition thereto, the heat of the fired ware passing through the cooling zone after leaving the tiring zone, may be utilized for heating the unired ware if' desired, as by admitting air to the cooling zone to be heated by contact with the cooling tired ware, and withdrawing such heated air and delivering it'to the preheating zone, as by passingA it through air forcing devices supplying air to the injector nozzles thereof, or by delivering it to the preheating zone by separate mea-ns.

My invention also contemplates means for withdrawing the' air, and products of combustion from thel preheating zone, either in thecase of a twin tunnel or single tunnel kiln, together with the vapors andl gases evolved during the preheating, oxidation, and water-smoking of the ware therein, and conveying such gaseous products away from the kiln to facilitate the operations of preheating, oxidation, and Water-smoking, and the residual heat of such gaseous products may be thereafter utilized in large part, as p by passing them through a drier or drivers for the ware, in order to prepare itfor iringvin the 'kiln or for other heating purposes, so that practcally all the available heat of the products of vcombustion may be utilized, and great economy of operation effected.

In the accompanying dra-wings, Y l

F ig. l, is a horizontal sectional view partly broke/n away, showing a twin tunnel kiln having myinvention embodied therein.

Fig. 2, is a transverse vertical sectional view through the firing chamber and firing ZOIIGS.

Fig. 3, is a transverse vertical section through one of the end portions of the kiln, constituting a combined preheating and cooling Zone.

Fig. 4, is a horizontal sectional view of a single tunnel kiln embodying my present invention, and provided with a single firing zone having a longitudinal row of furnaces on oppositesides thereof.

Fig. 5, represents a transverse vertical section through the firing Zone on the line, 5,5, of Fig. 4.

Fig. 6, represents a similar section through the preheating Zone on the line, 6, 6, of Fig. 4.

Fig. 7, is a horizontal sectional view simillar to Fig. 4, showing my invention applied to tion, the kiln comprises a centrally locatedfiring chamber, A, comprising two firing Zones separated by a central, longitudinal, vertical, impervious partition wall, and end sections, A-1,YA2, `extending longitudinally from the opposite ends of the firing chamber and being preferably of unitary 0r single tunnel structure without partitions, and being each a comf biiied pi'cheating and cooling Zone, the kiln being provided with two sets of goods conveying means extending entirely through the kiln, parallel to each other, and cach passing through both of the end sections and one of the firing zones. As goods conveying means, I preferably employ-parallel tracks, -upon each of which runs aline of tunnel ars, extending from one end of the kiln to the'otherin a well known way, the said cars being moved on one track inone direction, and upon` the other track in the opposite direction.

' The firing chamber comprises the lateral Vwalls, 1, the longitudinal partition wall, 2, and the roof portion which comprises preferably two separate crowns, 3, 3, forming a double tunnel structure and enclosing two firing zones, indicated at 4, 4. Each of the firing zones, 4, is provided with a longitudinally extending bridge wall, 6, on the outer side of the goods space indicated at 5, and separated from the outer wall, 1, so as to form a passage, 7, indicated in dotted lines in F 2, for the passage of the products of combustion from the furnaces, 8, over the top of the bridge wall and into the goods space of thel firing Zone. The bridge walls vare preferably .provided at their upper edges with inwardly extending portions, to assist in deflecting the products of combustion from the furnaces over upon the goods supported on the tunnel cars, indicated at 9, on the tracks 10, and in conjunction with thecurved-crown or roof, 3, to project them downwardly upon and through and around the ware. f n f The furnaces may be of any usual or desired character, according to the kind of fuel employed, and are preferably arranged in rows adjacent to the outer side of each firing zone.,

and are provided with means for independently controlling them. In the present instance, I have shown the furnaces, 8, provided with gasburners, indicated at 11, supplied with Y gas from a supply pipe, 12, by suitable pipes,

13, provided with controlling valves, 14, and air from an air pipe, 15, by means of suitable pipes, 1G, provided with independent controlling valves, 17. By this means, the several furnaces in each row may be independently "5 regulated, so asto produce the desired tem-` peratui'e within the contiguous portion of the firing zone, into which `it-s `products of combustion are discharged. The furnaces of each firing zone will be so regulated, as to provide a gradual rise of temperature from the entering end to the discharge end of each firing zone, which may be indicated by what lis termed a heat curve. It will be understood Vthat the heat curve of one-firing Zone Vwill be i the opposite of thatV in the other firing Zone,

which is made possible by the centrally located, impervious, longitudinal partition wall, 2. are employed, the particular regulating means will be necessarily modified in accordance with the character of the fuel,'to accomplish the same purpose. I prefer tovprovide each firing Zone between adjacent furnaces with transverse partit-ions indicated at18, 187,:eX-1

tending from the biidgewal'l to theouter wall vWhere other foi'ms of fuelthan gas of the furnaces, said transverse partitions-be-v ing preferably of vless height than the bridge wall, so that the discharge passages, 7, from the furnaces, 8, unite above said partitions, `18, and thus deliver a sheet vof flame, and lproducts of combustion extending the entire length of the firing zone, over the bridge wall vand `upon the ware in the goods lle' space of said Zone, the temperature of which l" at different points longitudinally of 'the' zone, will vary in accordance with theheat curve. Each of the firing zones is provided with means for withdrawing the products of combustion therefrom, after they have iinparted their greatest heat to the ware, in order to preventthem from passing into the end portions of the tunnel, and to enable their rey sidual heat to be yfurther ein-ployedin effecting the preheating, oxidation, and watersinoking of the unfiredware.

boing under rarification `or suction, so as to positively withdraw thejproducts of combustion from the adjaccntiiring zone. In this instance I have shown the eduction ports,

19, arranged in alignment with the transverse partitions,l8, and the eduction passages coinprising a horizontal passage, 20, connected with a vertical passage, 2l, leading to the collecting flue, 22, which is preierably located outside of the kiln and conveniently below the ground level.. These eduction passages may be independently controlled as by means of a silding damper indicatedat A3, accessible'through a passage, 24having a removable lclosure 25 l which O'ives access to the dampei, and also permits the lower portion of-theware within the firing zone to be actually viewed at a number of diiierent points corresponding with the locations of the eduction ports, 19, longitudinally of theliring zone. kIt will bel understood that in av twin tunnel kiln, there will be two sets of eduction passages and two of the collecting -iiucs, 22. According to Imy invention, the hot gases from each row of furnaces are conducted by the collectingflue, 22, toand delivered to one of the end portions of the tunnel, A1, or A2, and are introduced at separated point-s vlongitudinally of thev end sectionand'on the side thereof, adjacent tov the ycarsv of unfired .ware on its wayto the 4firing zone. As illustrated infFig 3 for example, which represents a section through one ofthe end portions Yof the kilnshownin Fig. l, each liuc, Q2, is

provided with a-plurality of` heat distributingpipes or passages indicated :at 26, and v27, being.; in this instance vertical passages,` 2G, conimunieating. with horizontal passages, 27, discharging into the' end section ofthe kiln adjacentto the `lower portion of the goods space therein, and adjacent to the ware which is to bepreheated. j

-- In order to secure the proper amount of oXygent-o insure the propel-oxidationv of the ware and to prevent scuinming, I arrange to admit with the products of combustion from the tiring zzone, a considerable quantity of .fresh atmospheric air which may, or n not be preheated. I-prefer to `introduce thisair directlyinto the heat distributing pipes or 'K passages, in such manner as to create a current or suction in the eduction flue, 22, and connected eduction passages, and for this purpose I conveniently provide the heat distributing pipes or passages with ejector no2;- zles indicated at 28, each connected by arpipe,

in each of said end 29,with an air supply pipe, 30, each of the nozzles, Q8, being controlled by an independentvalve, 3l.v

I prefer to provide a single air forcing device capable of supplying all of the atniosiheric air required in connection with the kiln, to avoid multiplication of air forcdevices, and in this instance for example, .l have shown a single fan or blower, 32, which is connected 'tor example by a pipe, 33, with an air supply pipe, l5, of the adjacent furnaces, and also to the air supply pipe, 30, for the injector nozzles, QS, on the saine side of the kiln, said air forcing device being also connected by a pipe, Sil, for eX- ainple, with the air supply pipe, l5, for the row of furnaces on the opposite side of the kiln, and to the air supply pipe, 30, for the injector nozzles on that side of the kiln. It will he seen that the discharge of jets of air through the nozzles, 28, will create a suction .in the adjacent collecting flue, Q2, and the eduction passages connected therewith, which will insure the withorawal of said gases from thel adjacent 'hrino zone, and their delivery to the end section of the kiln adjacent to the untired ware therein. rlhc valves, 3l, controlling the nozzles, 2S, may be independently regulated, so as to regulate the quantity of air admitted atv ditiiercnt points along thc length of the end section ott-ho kiln, together with the quantity of products of combustion admitted at such points, and secure the gradual heating of the unfired ware. If it is dcsired, the heat distributing passages, 2G, 27,

Vmay be provided with addi Ional dani pers asl indicated at 35 in Fig. for example.

It will be understood, that the un fired ware in each of the end sections of the kiln will also be heated by radiation and convection from the iii-ed ware on the other row ol cars sections. Iniay also provide for the adn'iisison of further quantities of atmospheric air into each end section if desired, at either one or both sides thereof, if it'is'necessary to admit additional quantities of air at sonic or all portions longitudinally of the said end sections to insure the proper oxidationof the ware, and prevent scuininin or eiscolorationV of the saine. In this instance, I have shown for example, a row of air inlets, 36, throughout each of the end sections as illustrated in Fig. 3, for example, connected with an air pipe, 37, which. may receive its air from the fan, 32, by connecting it with one of the adjacent air pipes, l5, for example, or otherwise, each of the air inlets, being provided with a suitable controlling valve or damper, 38. rlhese inlets, 36, are preferably located adjacent to the tired ware,

so that the air admitted therethrough may he' `heated 'hy contact with the tired ware before Cil rality ot'eduction passages indicated at 39, connected with a common eduction flue, 40, said eduction passages, 39, being arranged at different points longitudinally ot' the said end section, :for withdrawing` there'li'roin the prod,-

l'ucts of combustion admitted through the passages, 26 and 2i', together with thevapors, gases, periorn'ied its function of preheating, oxidizing and water-ranching the untired ware, so that the latter is continuously acted upon by the incoming products of combustion and air, while the water-sinoke77 etc., is being continuously with combustion. These products withdrawn from the end sections of the kiln still contain Y oi' which a current is induced in the eduction pipes, 89, eduction `flue, 4:0, connecting pipe,

Lil, and heating pipes, 42, to withdraw the vproducts 'from each end Vsection of the kiln,

and conduct themto the heating pipes of an ad] acent- Vdrier.

it will be understood, that, 1n the case oi a Ytwin tunnel kiln the construction and operation of the end sections A1 and A2, each of which constitutes a combined cooling and preheating Zone, will be identical, the relative positions of the inlet pipes and eduction pipes being simply reversed, Vas clearly shown in Fig. l. f

It will be understood, that, cars loaded with uniired products will be introduced into the y end section A1, at the point indicated at al,

and into the end'section indicated at 1&2, at the point indicated at a2, and will be moved,`

gradually on one of the' lines oity tracks through each end section wherethe wareis gradually heated by the cooling ware on the other track therein, and also by the hot products ot' combusti on injected into each end sec# tion in conjunction with iireshair from the nozzles, 28, supplying additional heatto the unlired Ware, and also :fresh air containing the necessary oxygen to properly oxidize it,

these nozzles preierably roviding the suc-- -tion tor withdrawing the products ot come bastion from Vthe iiring zone. By properly regulating the nozzles, 28, and controlling dampers, 35, the preheating o'li the ware can be very caretullyand accurately regulated from the timerv it ,enters the 'kiln until it 'reaches the ring zone through which it is to pass, so as to properly preheat and Waltervsmoke the brick without cracking, scumming or otherwise injurionsly affecting it, and the and other gaseous material. after it has Lrawn with the products oi" requisite amount of oxygen can be furnished throughout the travel of the uniired Ware, to etfeetthe thorough oxidation of the unfired VMware, Itfwill frequently be found that in certain clays the sulphur, for example, can be eliminated to the Vbest advantage between certain ten'iperatures, as the uniired Ware is gradually raised in. temperature in its progress toward the tiring zone, and'larger quantities of air can he admitted through the nozales, 28, adjacent to the Ware, within the portions of the end sections where such range of temperatures prevail, to insure the proper oxidation ot the sulphur and its elimination Different clays obfrom the tired goods.

iously require different conditions for efficient preheating, and my improved kiln provides :tor an extremely accurate control of the conditions within the preheating yZone throughout the entire length thereof, and the proper admission of air to supply the necessary oxygen. Additional quantitiesv ofair can also he admitted, when desired, through any of the air inlet 'pipes or passagesy, if required, and a very satisfactory transverse circulation will take place throughout each of the end sections of the kiln, which willv assist in preheating, water-smoking, andfoXidiZing of the unired Ware. v y s It will also be understood, that, the products of combustion and 'air admitted through each end section, will becomejmixed With the vawill be continuously withdrawn from each end section through the eduction pipes or passages, 39, and the eduction flue, 40thus further contributing to the rapid and thorough preheating, Water-smoking, and oxidation of the unfired Ware, and these'spent gases, air, and vapors Which Will still be ina highly heated condition, are conveniently conducted Y pors' and gases from the uniired Ware, and

through the driers out of contact With the air therein, for the purposeoiI drying theair before it is introduced into the kiln( *Y My invention also providesfor the iiring of the ware on'each row of cars in al separate, tiring zone wherein thedesired heat curve can.

be maintained, so that the Ware on'each line of cars will be raised to atemperature substantially equal to that of the enteringend of the firing zone through which-'it is to be passed, during its travel throughthe'appropriate end section A1, or A2, as the case may c be, and will then be4 subjected to gradually increasing temperatures in accordance with the heat curve maintained in the aligned firing zone, as lit passes through the latter, the fired goods from each firing fzone' passing through the end section at the yopposite end of the kiln from the one at which it entered, and

gradually giving ori its heat in cooling, to pre'-V heat the unfircd goods on the other track therein, as before described. y

In Figs. 4,5, and 6,` I have shown Va lsingle tunnel kiln embodying my 'invention and lheated by means of a row of furnaces or burnn ers located o neach side thereof. In these lig- Cil ures, the firing zone is indicated at A3, as located centrally of the length of the kiln and provided with the end sections, A4, and A5, of which the end section A4, is the preheating zone, andthe end section, A5, is the cooling zone, the kiln ybeing' constructed as a single tunnel throughout its length.` The various parts hereinbefore described, and which are found in these Figs. 4 to V6 inclusive, are given the saine reference numerals with'lOO added. The tiring zone comprises the side walls, 101, and crown, 103, and is provided interiorly with two bridge walls, 106, parallel tothe side walls and connected Vtherewith by the transversepartitions,118. Thetworowsoffurnaces or burners are indicated at 108, provided in this instance with burners, 111, supplied with gas bythe pipes, 113, providedwith regulating valves, 114, and connected to the supply pipes, 112, therburners being also supplied with air by pipes, 116, controlled by valves, 117, said pipes, 116, beingconnected with the air supply pipes, 115, so that the desired heat curve can be maintained in 'the firing zone. The products of combustion from each turnace or burner will pass upward between the partitions, 118, vandbe discharged downwardly upon the goods'in' the goods space between the bridge walls in the manner previously described, and will be withdrawn at each side ofv the tiring zone through the eduction ports,

119, and eduction passages, 120 and 121, under the control of the regulating means .or dampers, 123, passing inte the collecting fines, 122. Y

In this instance, as there is only onel preheating zone, the collecting flues, 122, are conveniently connected by a cross flue, 122% and one of said collectingflues, 122, is extended along one side of the preliieating zone as indicated in dotted lines in Fig. 4, where it communicates with the heat distributing pipes,

126 land 127, as clearly shown in Fig. G, the said pipes being provided with the air injecting nozzles, 128', controlled by valves 131, and connected with the air supply pipe, 130, in the same manner as previously described with reference to the previous figures, these nozzles serving to create the necessary suction in the collecting flues, 122. In this instance, the hot products of combustion discharged into the preheating zone may provide the only means for preheating the unlired ware, and each of the heat distributing passages is preferably provided with regulating means, as the dampers, 135, for example, so that the heat can be regulated throughout the entire length rof the preheating zone, while the quantity of air admitted at different points throughout the length of the preheating zone can be regulated by air inlet valves, 131. The preheating zone may also be provided with additional air inlet passages, 136, throughout its length controlled by independent valves, 138, and connected with an air supply pipe, 137, which may receive its air from the same source as the air pipe, 130, or from a ditlerent source, as preferred. rl`he preheating zone is also provided with eduction passages, 139, arranged at intervals throughout its length and being located, for example, on the opposite side from the heat'distributing passages, and connected with a header or collecting flue, 140, leading by a pipe, 141, to a heater, 142, in a drier, 143, and thence to a stack, 144, or these heated products may be conducted to any other point, or 'to any other apparatus in which their residual heat may be utilized.

The air for the gas burners and for the injector nozzles, 128, may be provided by any suitable air forcing means as a fan or blower, 132, which in this instance is connected with the pipes, 115, supplying the burners, and a pipe, 130, supplying the nozzles. This air may be heated in any desired manner, and for this purpose l find it convenient to draw the air from the cooling zone, A5, in which the hot fired products are parting with their heat, in order to utilize as far as possible, the heat from such fired products. For example, l have shown the cooling zone, A5, provided with a plurality of separated inlets indicated at 150, prcfe ably located adjacent to the discharge end of the kiln, and with eduction pipes, 151, preferably located at the other end of the cooling zone near the tiring zone, where the air would be subjected to the fired goods at their highest temperature j ust before it passes out, and these eduction passages, 151, may be connected as by a header, 152, and pipe, 153, with the fan or blower, 132, so that the air delivered to the burners and to the nozzles, 128, will be highly heated, and a portion of the heat of the tired products will be utilized both in the firing zone and in the preheating zone.

The operation of my improved kiln of the single tunnel form just described, will be substantially the same as previously set forth, and a further detailed description of its operation will be unnecessary.

ln Figs. 7, 8, 9, and 10, l have shown my invention embodied in a single tunnel kiln, in which the firing zone is provided with a single row of furnaces or burners located along one side only, the other features of the Iinvention being exactly as previously described with reference to Figs. 4, 5, and 6. ln these'ligures, the parts corresponding with those shown in Figs. 1 to3 inclusive, are given the same reference numerals with the addition of 200. ln this cas-e, the iiring zone indicated at A, as shown in section in'Fig. 8, comprises the side walls, 201, and the crown, 203, and is provided interiorly with a single bridge wall, 20G, connected with the adjacent side wall by the transverse partitions, 218.

28 represents thevfurnaces providedwith burners, 211, supplied with gas from the gas supply pipe, 212, by pipes, 213, having the independent control valves, 214, and with air from the air supply pipe, 215, by pipes, 216,

having independent control valves, 217. The tiring chamber is also provided with a plurality of eduction ports, 219, connected by passages, 220 and 221, with the collecting flue,

222, in the manner previously.,described, said passages being controlled by independent ineansvas the dampers, 228.

The preheating zone of this single tunnel kiln indicated at A8, and shown in detail in F ig. 10, is provided witlrthe heat distributin g pipes or passages, 226 and 227, provided with injector nozzles, 228, controlled by valves, 231, and connected with the air supply pipe,

230, the heat distributing passages being prodrier, for example, 24.3, from which heater they pass to a stack, 244, all these parts being combined and operated in the manner hereinbefore described.

The coolinfT zone Vherein indicated at A7 and shownin cross section iu Fig. 9, is shown as provided with a plurality offair inlets, 250,

, for admitting fresh air to the cooling section for the purpose of heating it, and cooling the ware, which heated air is withdrawn from the cooling zone through eductionpassages,v 251, into a header, 252, and thence by a pipe, 253, into a fan or blower, 232, connected with the air pipe, 215, supplying the bui-ners, and the Y air pipe, 230, supplying the injector nozzles,

228, and it may also be `connected with the auxiliary air pipe, 237. Itv will be understood, that, the necessary air for these various air pipes may be set in motion by air forcing devices of any desired type, and that separate air forcing devices may be employed for supplying each of the air pipes, if necessary or desirable. I iind it advantageous and economic, however, to use a single air forcing device for the kiln, as diagraininatically indij cated in the drawing. It willvbe understood, that a single line of goods conveying' means extends through the kiln from one end to the other, preferably a lin-e of tunnel cars on track rails extending throughout the length of the kiln.` The uniired ware enters at the outer end of the preheating zone, A8, and will pass slowly therethrough and be gradually heated,

. water-smoked and oxidized as hereinbefore set forth.l and being raised to substantially the temperature of the entering end ofzthef tiring zone, AG, in passingthrough the pre- .the air admitted inayalso be heated from thel fired products inthe cooling zone A7, so as to assist in. cooling thelired ware and utilize a portion of the heat thereof for preheating purposes. This is especially desirable in single tunnel kilns, in which the heat from the fired ware cannot be directly imparted to the unlired ware inthe preheating chamber, as it can be in the twin tunnel kiln illustrated in Figs. 1 to 3 inclusive, in which it is not necessary to heat the air, although it may be so.

heated even in a twin tunnel kiln in any usual or desired mannen as yby a recuperator' through which the wastek gases, etc., are

passed, if found to be desirable. vThe pre heated ware will be fired in the Iiring zone, A6, and coo-led in passing through the-cooling zone, A7, in the manner hereinbefore de#y scribed with reference to Figs. 4 to 6 inclusive.

In carrying out my invention, it will be noted that a very accurate control of, the. tiring zone is secured throughout its lengthv in all forms of the invention for the purpose of maintaining the desired heat curve therein, and the-products of combustion are withdrawn and utilized directly in combination with fresh air, to supply .the necessary oxygen, in preheating, water-smoking, and oxidizing the unfired ware, thus effecting great economy of fuel, the heat from which is lirst expended in the firing zone by direct application to the ware, and then further used directly in contact with the unlired ware in the preheating zone, from which the products of combustion, together with vapors and gases l produced in the preheating, water-smoking and oxidation of the unred ware, are continuously removed and .conducted to a point where their residual heat may be further utilized, while their removal frointhe pre-V hea-ting zone facilitates thepreheating, oxidizing, and wateresmoking of the unired ware. ,y

It will also be seen, that, `the preheating zone is under accurate control throughout its length as to both temperature and the `amount of fresh air and oxygen supplied, so that the ware can be gradually raised in temperature and sufi-cient oxygen can-be supplied at difhustion into the tiring Zone, a preheatir Y members a firingrzone, provided with heating :navarral ferentpoints throughout' the length of the preheating-zone, to accomplish the oxidation and removal of objectionable ingredients in the clay in the most etilcient mannerx lt Will also he noted, that, the construction of the kiln isrextremely' simple and comparatively inexpensive, which results in a minimum initial cost oi' construction and minimum expense oit upkeep and repair.

What I claim and desire toolotain hy Letters Patent is i* '1. A tunnel kiln con'iprising among its members a. firing Zone, provided with heating I means discharging their products ot combustion into the tiring Zone, a preheating one co1 iprising ainoiro' its .means discharging their products oi: ce'

zone extending longitiujlinallyY one end of the firing zone, a cooling sono eide/nih ing longitudinally from the other end ot the firing zone, goods conveying means extending through all oli said Zones, and means `for withdrawing the products of combustion from the tiring' zone and deu livering them into the preheating none iior preheating, Water-smoking, and 'oxidizing the uniired produc-ts therein, and means for introducing air into the prelieating zone to supply additional quantities or' oxygen to sist in the oxidizing of the untired products. 3.- A tunnel kiln comprising among members a firing zone, provided with heating means discharging' their products o'l coni? hustion into the tiring Zone, a prelieating zone extending longitudinally 'troni one of the iring Zone, a cooling zone longitudinally from the other end or ine ing zone, goods conveying` means extent i through all of said Zones,'and means 'for withn drawing the products of con'ihustion from Vthe tiring zone and delivering them into the preheating zone for preheating, ivater-siiotng, and oxidizing the untired products therein, and means for introducing Jfresh air into the preheating zone to furnish additional oxj, feu for oxidizing the unfired products, and means for heating the said air previous to its intro duc-tion into the preheating zone.

' fl. A tunnel kiln con'iprising among its memhersa tiring Zone, provided with heating means discharging their products ci comhustion into `the lliring' Azone, a preheating Zone extending longitudinally from one end of the tiring zone, a cooling zone extending longitudinally troni the other end o' the liring zone, goods conveying means extending through lall ot said zones, means for Withdrawing the products of f'omliu: ion ron'i the tiring zone uf'ithout permitting appreciable longitudinal flow thereof and nic-ans forcenducting them outside of the kiln into the preheating zone at separaed poi ts longitudi-- nally thereof, and moans iro' independently regulating the admission o' ,aid products oli combustion into the preheating zone said separated points.

5. tunnel kiln con'iprising among its niemhei's a ring Zone, provided with heating means discharging their products or combustion into the iiringfzone, a preheating zone c1;- tending longitudinally from one end of the liring Zone, a cooling zone extending longitudinally ironithe other end ol th e tiring zone, goods conveying means extending through all of said Zones, and means for withdrawing the products or combustion from the tiring zone and delivering them into the n'eheating zone at separated points longitudinally thereof", and means for independently regulating the admission oit said products ot condnistion into the prelieating Zone at said separated points, means for admitting i'i sh air into the preheating zone at separated points longitudinally thereof, and independent 'regulating means' for independently regulating the admission ot air at said separated points.

6. A tunnel kiln comprising-f among its members .a firing Zone, provided with heating means discharging their products oi condiustion into the tiring zone, a prelieaiing zone er;- tending loiie'itiulinally troni one i liring zone, a cooling zone extcndn dinally 'from the other end oi'l the i lng Yamic, goods conveying means ei ending through all ot'said Zones, means for \=.'itln;lrau'ing products ot con'ihustion troni the nring Zone without permitting appreeiahle lone' udinal ilow the and delivering the: to the prelieating zone for preheating, ivatensmoliing, and oxidizing the uniired infoducts the in, means lior admitting air into the eo ,Jig zone lor heating said air and assisting in cool@ ing the lired products, and means V for ivitlidrawing the heated air from the coolin :ioneA and admitting it into the preheating Zone, to assist in the preheating, Water-smokino', and i'ixidizing ot the unfired products therein.

7. A tunnel kiln comprisng among its incinhers a tiring zone, provided with heating means discharging their prodncts ot conihustion into the tiring zone, a preheati extending longitudinally Vtroni one firing Zone, a cooling Zone extending l itudinally 'from the oth Vr end oi'l the tiring Aone. goons conveying means extending through all oi.' said Zones,

mea* s forVwitlnlrawing they air at said separated points.

products of combustion from the. firing zone without permitting appreciable longitudinal flow thereof and delivering them into'the preheating zonet-or preheating, water-s1noking, and oxidizing the uniired products therein, means `for admitting air into'the cooling zone 'for heating said air and assisting in cooling the .tired products, and means for withdrawing the heated air from the cooling zone and admit-ting it into the preheating zone at separated points longitudinally thereof.

8. A Vtunnel kiln comprising among its members a firing zone, provided with heating means discharging their products ot combustion into the liring zone, a prelieatin g zone eX- tending longitudinally from one end oi the firing zone, a cooling zone extending longitudinally from the other end of the tiring zone, goods conveying means extending through all of said zones, and meansfor Withdrawing the products of combustion from the firing zone and delivering them into the preheating zone at separated points longitudinally thereof, independent regulating means for independently regulating the admission of the products et combustion at said separated points, means for admitting air to the cooling zone Yfor heating it and assisting in cooling the fired products, means tor withdrawing said heated air from the cooling zone and delivering it into the prelieating zone at separated points longitudinally thereof, andy independent regulating means 'for independently regulating the admission ot such heated 9. A tunnel kiln comprising Vamou g its members a firing zone, provided with heating meanspdischarging their products ci' combustion into the firing zone, a prehcating zone extending longitudinally from one end ot the iiring zone, a cooling zone extending longitu,

diiially from the other end of the tiring zone, goods conveying means extending through all of said zones, means for conducting the products of combustion from the tiring zone to the preheating zone, and air injecting means discharging fresh air into the preheating zone together with the products of combustion, said injecting means being constructed to elffect the necessary suction for withdrawing the products of combustion from the iii-ing zone and delivering them into the preheating zone.

10. A tunnel kiln comprising among its members a tiring zone, provided with heating means discharging their products of combus tion into the firing zone, a preheating zone extending longitudinally from one end of the liring zone, a cooling zone extendinglongitudinally from the other end of the tiring zone, goods conveying means extending through all of said zones, said kiln being provided with passages for withdrawing the products of combustion from the firing zone and delivering them into the-preheating zone, including ing the products of combustion from the firing zone and delivering them with'said air into the relieating zone.

11. A tunnel kiln comprising among its members iiring zone, provided with heating means discharging their'products of combustion into the tiring zone, a preheating zone extending longitudinally from one end otitlie"` .tiring zone, a cooling zone extending 'longitudinally from the other end of the firing zone, goods conveying means extending through all of said zones, said kiln being pro'- Vided with passages for withdrawing the products ot' combustion from the tiring Zone and delivering them into the preheating zone,

including a series of heat distributing passages discharging into the preheating zone at diilerent points longitudinally thereof, air iniecting nozzles adapted to discharge air into said heat distributing passages, means lor supiilying air under pressure to said noz-v zles to deliver air intoftl'ie preheating zone,

and i'or effecting the necessary suction for withdrawing the products of combustion ii'om the firing zone and delivering .them with said air into the preheating zone, and

- in dependent regulating devices for said nozzles. I Y

l2. A tunnel kiln comprising among its members a liring zone, provided with heatingmcans discharging their products of combustion intov the firing zone, a preheating zone extending longitudinally trom'one end of the firing zone, a cooling zone extending longitudinally 'from t-he other end of the firing zone, goods conveying means extending through all et said zones, said kiln being provided with passages for withdrawing the products et combustion from the iiring zone and delivering t'hein into the preheating zone, including a series ot heat distributing passages discharging into the preheating zone at different points longitudinally thereof, air injectiiig nozzles adapted to discharge air into said heat distributing passages, and means for supplying air under pressure to said nozzles to deliver air into the preheating zone, and tor effecting the necessary suction for withdrawing the products ot combustion means discharging their products of combus-A so' l freni the tiring zone and d@ 1i meagre f amg Y through all of saidzones, conducting means for cfzfnilucting the products ot combustion 'the preheating zone, including a plurality of heat cistributing passages discharging into the preheating zone at dilerent points longitudinally thereof, a plurality of air insaid heat distributing passages, means for admitting air to the ooolingzone to heat said 'air and in cooling the .tired Ware, and means tor withdrawing the heated air trom the cooling zone and delivering it under pressure to said nozzles.

MJA tunnel kiln comprising among its nembers a tiring zone, provided With heating means discharging their products of combustion into the firing zone,` a preheating zone extending longitudinally from one end oitI the firing zone, a cooling zone extending longitudinally' vfrom the other endv of the liring zone, goods conveying means extending through all of said zones, conducting means for conducting the p-roducts of combustion from the tiring zone and delivering them into the preheating zone, including a. plurality oi" heat distributing passages discharging into the vpfeheating zone different points longitudinally thereof, apluralityl oitV air injecting nozzles each dischargingv into one of said heat distributing passages, means for admitting air toy the cooling zone'to'- heat. said air and assist in cooling the tired Ware,

and means tor: withdrawing the heated air from the cooling zone and Idelivering it under pressure to said-nozzles, andindependent regulating means for each of said nozzles.

l5, A tunnel kiln comprising among its members a Vtiring zone, provided with heating means discharging their products of com-bustion into. the liring zone, a preheat-in g zone eX- tending lonfitudinally from one end of the tiring zone, a cooling zone extending longitudinally from the otherendf of the firing zone, goods conveyingY means extending` through all oiE said zones, conducting means for conducting the product-s of combustion from the tiring zone and delivering them into the preheating zone, including a plurality: of'

heat distrilniting passages discharging into the preheating zoneiat diierent points longitudinally thereof, a plurality oit-air injecting nozzles each discharging into one oi siad heat distributing passages, means Yfor admitting air tothe cooling zone to heat said air and assist in cooling the tired ware, and means for withdrawing the heated air from the cooling'I zone and delivering it under pressure to said nozzles, and independent regulating means for each oi said heat distributing passages,

",ecting nozzles each discharging into one or'v and ari-independent regulating means for each-ot' said nozzles. 16'. A; tunnel kiln comprising o among its members a tiring zone, provided With heat- Y ing means discharging their products o1'l combustion into the tiring zone, a preheating zone cimending longitudinally from one end oit the iii' g zene, a 'cooling zone extending longitudinally from the other end of the firing zone, goods conveying means extending through all of said zones, and means for Withdrawing the products of combustion Jfrom the tiring zone and delivering them into the preheating zone l'or preheating, Water-smoking, and oxidizing the unlired products therein, and means tor- -withdranving the products of combustion from the preheating zone, together with gases and vapors produced therein,

17. A; tunnel lriln comprising among its members a firing zone, provided with heating means dischai ring their products of combustion into the iii-ing zone, a preheating zone extending longitudinally from one end of the iiring zone, a cooling zone extending longitudinally `from the other end or the tiring zone, goods conveying means extendingY therein, means for withdrawing the products of combustion together with gases and vapors, at separated points longitudinally of the preheating zone, and independent regulating means, 'for independently regulating the Withdrawal ot saidproducts of combustion, gases, andvapors at said separated points.

181 A tunnelflilnV comprising among its members a iiring zone, provided 'with heating means discharging their products oi combustion into the i'iring zone, a preheating zone extending longitudinally from one end ot the tiring zone, a cooling zone extending longitudinally from the other end oit the tiringl zone, goods conveying means extending through all ot said zones, and means for Withdrawing the products off combustion from the firing zone and deliver-ing them into/the preheating zone for preheating, Water-smoking, and oxidizing the unred products therein, means for introducing fresh air into the preheating zone to furnish additional quantities of oxygen, and means for continuously withdrawing Jthe products of coinbustion and air, together with gases and vapors formed in the ercheating zone."

19. A tunnel kiln comprising among its members a tiring zone, provides with heating means discharging their products of combustion into the tiring zone, a'preheating zone' lll) Yzone, goods conveying means extending CII through all of said zones, means for conducting the products of combustion from the liring zone to the prelieating zone, including a plurality of heat distributing passages discharging` into'the pi'elieating zone at different points longitudinally thereof, independent regulating means for said heat distributing passages, means for delivering fresh air into the preheating zone at different points longitudinally thereof, independent regulating means for independently regulating the admission of air at said different peints, and means for continuously withdrawing from the p reheating zone the products of combustion and air, together with gases and vapors at different points longitudinally of the prevheating zone.

20. A tunnel lriln comprising among its members a firing zone, provided with heating .means discharging theirl products of combustion into the firing zone, a preheating zoneextendin g longitudinally from one end of the firing zone, a cooling zone extending longitudinally from the other end of the liring zone, goods conveying means extending ythrough all of said zones, means for conducting the products of combustion from the firing .zone to the preheating zone, including a plurality of heat distributing passages discharging into the preheating zone at different points longitudinally thereof, a plurality of injector nozzles each discharging into one of said heat distributing passages, means for delivering air under pressure to `said nozzles, independent regulating means for said nozzles, and eduction passages for withdrawing the products of combustion and air, together with gases and vapors, from the preheating zone, located at different points longitudinally thereof.

2l. A tunnel kiln lcomprising among its members a firing zone, provided with heating means discharging their products of coinbustion into the tiring zone, a preheating zone extending longitudinally from one end of the firing zone, a cooling zone extending` longitudinally from the other end of the liring zone, goods conveying means extending c through all of said zones, and means for withdrawing the Aproducts of combustion from l the firing zone and delivering them into the preheating zone for preheating, water-smoking, and oxidizing the unired products f therein, means for admitting air to the cooling zone, to heat said air and assist in cooling the fired products, means for withdrawing i said heated aiil from the cooling zone and discharging it into the preheating zone, to assist in preheating, water-smoking, and oxidizing the unfired products. and means for withdrawing the products of combustion and air, together with gases and vapors from the prelieating zone.

22. A tunnel kiln comprising among its members a. firing zone, Aprovided with heating means discharging their products of conibustion into the firing zone, a preheating zone extending longitudinally from one end of the firing zone, a cooling zone extending loiigitudinally from the otherend of the firing zone, goods conveying ineans extending through all of said zones, means for conf sages, means for withdrawing heated airy from the cooling zone and injecting it under pressure into Vsaid heat distributing passages, to supply additional heat and oxygen to the preheating zone and effect the withdrawal of the products of combustion from the iii-ing zone, and means for withdrawing the products of combustion and air, together with gases and vapors from the preheating zone.

28. A tunnel lriln comprising among its members a firing zone, a plurality of furnaces jacent to said furnaces for withdrawing the products otconibustion from the firing zone, a preheating zone extending longitudinally arranged longitudinally thereof, yand pro-rV vided with independent heat' regulatingv means for maintaining a ii'edeteiiniiied heatv from one end of the firing zone, a cooling zone extending longitudinally from the other end of the firing zone, goods conveying means extendingthroughall of said zones,- a heat collecting flue connected with the said eduction passages, heat distributing passages ,con-

nected with said flue and discharging intol the preheating zone at different points longitudinally thereof, and means 'for vpositively withdrawing the vpro ducts of combustion from the firing zone and delivering them into the prelieating zone.

24;. A ltunnel kiln comprising among its members a firing zone, a plurality of furnaces arranged longitudinally thereof, and provided with .independent heat regulating means for maintaining a predetermined heat curve within the firing zone, said firing zoney being provided with eduction passages adj a- Y 'cent to said furnaces for withdrawing the products of combustion from the firing zone,'

a preheating zone extending longitundinally from one end ofthe firing zone, a cooling zone extending longitudinally from the other end of the firing zone, `goods Yconveying means extending through all of said zones, a heat collecting flue connected with tlie'said eduction passages, heat distributing passages conv nected with said flue and discharging into the preheating zone at different points longitudinally thereof, an injector nozzle discharging into each of said heat distributing passages, and means-for delivering air under pressureito said nozzles to furnish additional oxygen to thevpreheatingzone, and to effect the positive Withdrawal of said products of eombusition from. the iirino zone and their being provided with eduction passages ad] acent to said furnaces for withdrawing the products of combustion from the iii-ing zone,"

a preheating zone extending longitudinally from one end of the firing zone, a cooling zone extending longitudinally from the other end of the firing zone, goods conveying means extending through all of said Zones, a heat collecting flue connected with the said eduction passages, heat distributing passages connected with said flue and discharging into the preheating zone at different points longitudinally thereof, and injector nozzle discharging into each of said heat distributing passages, means for withdrawing air from the cooling zone and delivering it under pressure to said nozzles, for supplying heat and oxygen 'to the preheating zone and effecting the positive Withdrawal of the products of combustion from the firing zone, and their delivery to the preheatingzone. 26. A tunnel kiln comprising among its members a firing zone, a plurality of furnaces arranged longitudinally thereof, and provided With independent heat regulating means for maintaining a predetermined heat curve Within the iii-ing zone, said firing zone being provided with eduction passages adjacent to said furnaces for withdrawing the products of combustion from the firingzone, a preheating zone extending longitudinally from one end of the firing zone, a cooling zone extending longitudinally from the other end of the iiring zone, goods conveying means eX- tending through all of said zones, a heat collecting flue connected with the said eduction passages, heat distributing passages connected With said flue and discharging into the preheating zone at different points longitudinally thereof, means for delivering fresh air to the preheating zone, and eduetion passages for the preheating zone located .at separated points longitudinally thereof, for Withdrawing the products of combustion and air, together With gases and vapors from the preheating zone.

In testimony whereof I afliX my signature.

WILLIAM LEE HANLEY, JR. 

